Fill neck for a fuel tank



FIG. 1 is a side view of an ornamental design for a fill neck for a fuel tank according to the invention;

FIG. 2 is a bottom view of the design of FIG. 1;

FIG. 3 is a front view of the design of FIG. 1;

FIG. 4 is a top view of the design of FIG. 1; and,

FIG. 5 is a back view of the design of FIG. 1. 

The ornamental design for a fill neck for a fuel tank, as shown and described. 